Long-term survival after definitive proton beam therapy for oligorecurrent esophageal squamous cell carcinoma: a case report

BACKGROUND: Radical esophagectomy for esophageal squamous cell carcinoma has improved survival, but the rate of recurrence is high. Patients of recurrent esophageal squamous cell carcinoma after failure of chemotherapy have a poor prognosis. We herein report the achievement of long-term survival after definitive proton beam therapy for oligorecurrent esophageal squamous cell carcinoma after failure of chemotherapy. CASE PRESENTATION: A 60-year-old Japanese man was diagnosed as having squamous cell carcinoma of the lower thoracic esophagus (cT2N0M0, stage IIA). He underwent two courses of neoadjuvant chemotherapy with cisplatin and 5-fluorouracil, and esophagectomy with three-field lymphadenectomy was performed. Microscopic findings after resection showed two lymph node metastases (ypT2N1M0, stage IIB). Five months after resection, a computed tomography scan revealed a solitary liver metastasis in the S4 area. He underwent three courses of chemotherapy with cisplatin and 5-fluorouracil; however, positron emission tomography revealed two lymph node metastases. Surgeons recommended second-line chemotherapy, but the patient refused chemotherapy and requested proton beam therapy. We performed proton beam therapy without chemotherapy for the liver metastasis and lymph node metastases, with total doses of 79.2 and 60 Gy relative biological effectiveness, respectively, according to the tumor location. An acute side effect of grade 1 dermatitis occurred after proton beam therapy, but there was no acute or late complication of more than grade 2. The patient remains in complete remission 5 years after treatment without surgery or chemotherapy. DISCUSSION AND CONCLUSIONS: Proton beam therapy exerted a curative effect on oligorecurrent esophageal squamous cell carcinoma. This is the first report on the achievement of long-term survival after definitive proton beam therapy for oligorecurrent esophageal squamous cell carcinoma.